Yes, being panic in cases like this will not earn you any good. I know this is usual to us but we can avoid this if we will set target for ourselves. Make a good limit on the possible profit you will take as well as the limit for lost so you will not have bad decision and will not have any regrets.
When you see the situation in the market when the price is going down you must be patient and still be waiting for better time. Because market is crazy scene, and it always grows up after the falling down.